A machining head replaceable rotating tool is known wherein (a) a fastening male screw and a fastening female screw disposed on respective shaft centers of one and the other of a machining head and a holder are threadably engaged with each other to concentrically and removably attach the machining head to a tip portion of the holder; (b) the machining head and the holder are disposed with abutting surfaces abutted against each other in a fastened state when the fastening male screw and the fastening female screw are threadably engaged; and (e) the machining head replaceable rotating tool is integrally and rotationally driven via the holder in a tool rotation direction causing the fastening male screw and the fastening female screw to be fastened by a machining load to perform predetermined machining with the machining head while the abutment of the abutting surfaces prevents the fastening male screw and the fastening female screw from being further fastened by a machining load (see Patent Document 1). With such a machining head replaceable rotating tool, since a holder can be utilized many times by replacing only a machining head made of expensive material such as cemented carbide, for example, and a plurality of types of machining can be performed with a common holder by preparing a plurality of types of machining heads, a waste of resources can be suppressed and a tool cost is reduced in either case.